126 REPORT—1849. 
it susceptible of small quantities passing through it under light pressure; this may 
be illustrated by what takes place in actual practice in dry meters, and shows the 
difference between the wet and the dry meter. The wet meter, a simple wheel or 
drum revolving partially in water, without a click, clack or valve; its passages are 
alternately sealed or immersed in water, preventing the possibility of escape of gas 
without being registered. The dry meter consists of diaphragms, valves, levers, 
cranks, stuffing-boxes, &c., and may be compared to two or three steam-engines, 
the only difference being the diaphragms instead of cylinders and pistons. In prac- 
tice, as may be expected, the valves become defective, and oftentimes allow large 
quantities of gas to pass unregistered, and at all times small quantities, unless when 
new and perfectly clean and oiled ; whereas the wet meter, until actually worn out 
by time or corrosion, continues to register every particle of gas passing through it. 
These two descriptions, therefore, will serve to illustrate the two kinds of water 
meters—the one consisting of valves, pistons, &c., the other without, as brought 
before the notice of the British Association by the patentee, and in which the press- 
ure is put under perfect control before the water enters the body of the meter, and 
so limits the supply to a maximum quantity, and thus gets rid of the evil of being 
over-driven and derangement. The next question is, how to get a supply to the 
upper rooms of a house. No difficulty can occur here if the pressure of water be 
always on and sufficient to reach such elevation; there can be no necessity to mea- 
sure the water before it ascends; it is only necessary to place the meter at the high- 
est point ; the water will of course descend by its own gravity, and supply every room 
or closet below, thus ridding this meter of the difficulties which the other had to 
contend with, and reducing it to one of easy construction, comparative cheapness, 
and not easily deranged. Its durability may be calculated to be as great as that of 
the gas-meter, which often goes twenty-five and thirty years without repair. A 
greater durability in this may be looked for, from its always working in pure water, 
and from its extreme simplicity ; the measuring-wheel or drum being similar to that 
in the gas-meter, the regulating apparatus which reduces the pressure to the proper 
level, at fixed periods, being accurately measured, and all the parts self-acting ; and 
it is supposed that now Water Companies have a fair chance to get paid for all they 
sell, it will be to their interest to keep up an uninterrupted supply; although this 
does not prevent the old cistern being supplied by meter, it is evident that a larger 
meter would be required. By the new system, the whole apparatus may very con- 
veniently be placed inside the house free from the effects of frost, the annoyance 
from this and short supplies; to these advantages may be added the assurance of 
justice and equity between buyer and seller. 

The Sheet-Metal Moulding Machine. 
By Ricuarp Roserts of Manchester. 
This machine, of which a drawing, on a scale of one and a half inch to a foot, was 
shown, is furnished with two shafts, which project beyond one of the side-frames, 
in which the lower shaft turns; the upper shaft is mounted on a balance swing- 
frame, and is connected by spur gear with the lower shaft, in such a way that the 
distance between them may be adjusted to any required extent, without altering the 
depth of the wheels in gear. On the projecting ends of these shafts are put the 
rollers with which the mouldings are to be formed. The lower roller is generally 
in one piece only ; but the upper roller is made in one or more parts transversely, 
as may be best adapted to form the required mouldings. These parts are made to 
approach each other, by being slid along the shaft, which is hollow, by means of a 
screw within, that acts upon the back part of the top roller, by means of a cotter 
that passes through the shaft and the screw, and on the front part by means of a 
nut, which is screwed from time to time by hand. 
The machine is furnished with a third roller, by which it is adapted for giving any 
degree of curvature to the mouldings. For some mouldings, two or more pairs of 
rollers are used in succession. When two pairs are used, the first pair is to crease 
the metal preparatory to its being formed into the required moulding by the second 
pair of rollers. 
In another drawing, sections of a railway bar or rail, in two stages of manufac- 

